Prevention of type 2 diabetes mellitus (T2DM) is a high priority within the VHA. Despite the availability of evidence-based strategies to prevent T2DM, engagement in these strategies is low among at-risk Veterans. A key opportunity to engage at-risk Veterans in interventions to prevent T2DM is when they are informed they have prediabetes through a screening test and communication of these test results through their Patient Aligned Care Team (PACT). The design of such communications could potentially be improved by incorporating state-of-the-art insights from behavioral economics and health psychology. Yet, it remains unclear just how VHA communications to patients diagnosed with prediabetes could be modified to improve their engagement in evidence-based preventive strategies. Through this CDA, I will build on my prior training in behavioral economics to gain content expertise in health psychology and related disciplines as well as acquire advanced skills in experimental design and mixed methods evaluation. With this training and support from my CDA mentors, I will achieve 3 aims. Aim 1: To describe at-risk Veterans' current engagement in behaviors to prevent T2DM and the mediators of this engagement. We will survey 189 non-diabetic Veterans in the VA Ann Arbor Healthcare System (VAAAHS) who have a body-mass index (BMI) ? 30 kg/m2 or BMI ? 25 kg/m2 and an obesity-related comorbidity. These Veterans will be asked about their engagement in behaviors to prevent T2DM and mediators of this engagement such as risk perception, motivation, and awareness of and preferences for preventive strategies. Aim 2: To examine the effects of receipt of a prediabetes diagnosis on at-risk Veterans' weight and engagement in behaviors to prevent T2DM. We will conduct a pilot randomized trial among the same 189 non-diabetic Veterans from Project 1 in which we will randomly assign 126 of these Veterans to undergo screening for T2DM using a hemoglobin A1c (HbA1c) test. The 63 Veterans who we project will have HbA1c values in the prediabetes range will receive that diagnosis and preventive recommendations from their PACT provider via brief standardized counseling. All 189 Veterans will have their weight tracked over the next year and will be surveyed immediately after the screening and brief counseling process, at 3 months, and at 1 year. Then we will compare changes in weight, engagement in behaviors to prevent T2DM, and mediators of this engagement between the 63 Veterans who we project will have prediabetes and the 63 Veterans who were not screened. Among the 63 Veterans with prediabetes, we will conduct 20 semi-structured interviews to gain insights into the effects of this diagnosis and brief counseling. Aim 3: To identify the effects of 4 strategies from behavioral economics and health psychology on weight, HbA1c, and engagement in behaviors to prevent T2DM among Veterans with prediabetes. We will conduct a fractional factorial design experiment to evaluate the effectiveness of 4 innovative strategies from behavioral economics and health psychology in promoting weight loss, decreasing HbA1c, and increasing engagement in behaviors to prevent T2DM among 144 Veterans in the VAAAHS who are identified as having prediabetes through an HbA1c test. We will conduct qualitative evaluations of the acceptability of these strategies to patients. In this CDA, I will use innovative experimental methods and apply cutting-edge behavioral techniques to more effectively engage at-risk Veterans in evidence-based strategies to prevent T2DM. Insights generated from this research will be readily exportable to other high-priority conditions in which Veteran engagement in preventive behaviors is essential and could be improved. Through these projects and targeted additional training, I will acquire the content expertise and methodological skills I need to achieve my long-term career goal of becoming a national leader in developing, evaluating, and disseminating scalable VHA prevention strategies that are based on key insights from behavioral economics and health psychology.